1. Field
The embodiments relate to a network test apparatus connected to a relay apparatus being a test object. Particularly, the network test apparatus conducts the plurality of tests by transmitting/receiving Operations Administration Maintenance (OAM) frames containing kinds of the test indicating the respective plurality of tests for Ethernet-OAM to/from the relay apparatus.
2. Description of the Related Art
Conventionally, the Ethernet has been used to construct a LAN (Local Area Network). Recently, communication carriers use the Ethernet to construct a wide-area network such as the WAN (Wide Area Network). For example, a wide-area Ethernet using the layer 2 of the Ethernet is implemented mainly in a Point-to-Point Network or a multipoint-connection Layer 2 Virtual Private Network.
The communication carriers that provide the wide-area Ethernet need to manage and maintain the network itself by sensing defects in a plurality of relay apparatuses (for example, LAN switches) or a line used to construct the wide-area Ethernet. For such management or maintenance, the carriers use SNMP (Simple Network Management Protocol) being a management protocol of TCP/IP (Transmission Control Protocol/Internet Protocol).
Generally, as a technique to maintain and manage various conditions that occur in the layer 2, the Ethernet-OAM (Ethernet-Operations Administration Maintenance) is used. The Ethernet-OAM has been standardized as “Y.1731” (Non-patent Document 1: “Ethernet-OAM”, [online], [searched on Jan. 9th, 2007], Retrieved from the Internet: <URL: http://itpro.nikkeibp.co.jp/artice/COLUMN/20060720/243861>) by the ITU-T (International Telecommunication Union Telecommunication-Standardization Sector). IEEE (The Institute of Electrical and Electronics Engineers, Inc) has also proceeded with standards work as the “IEEE802.1ag” (Non-patent Document 2: “802.1/802.3 Standardization Trend”, [online], [searched on Jan. 9th, 2007], Retrieved from the Internet: <URL: http://wbb.forum.impressrd.jp/report/20060922/280>).
Describing an overview of the Ethernet-OAM, the Ethernet-OAM is a specification to maintain and manage the various conditions that occur in the layer 2. To use the Ethernet-OAM, an L2 switch used in a subject Ethernet, for example, needs to implement the Ethernet-OAM. Therefore, it is tested whether a relay apparatus such as an L2 switch implements (conforms to) Ethernet-OAM or not for maintenance and management using the Ethernet-OAM in a real environment.
Specifically, as shown in FIG. 27, in the Ethernet-OAM, a managed group is referred to as a MEG (Maintenance Entity Group), a terminating apparatus in a MEG is referred to as a MEP (MEG End Point), a relay apparatus in a MEG is referred to as a MIP (MEG Intermediate Point), and a communication section between two MEPs is referred to as an ME (Maintenance Entity).
The above terms will be described specifically as follows. An ME is a section to conduct various tests using an OAM frame. A MEG is a collection of MEs. For example, in P2P connection, an MEG includes only a single ME. On the contrary, in the case of multipoint connection, an MEG includes a plurality of different MEs. A MEG is assigned with an ID (character string) referred to as a MEGID, which is defined differently by ITU-T and IEEE.
Also, many levels to constrain the operation of a MEP and MIP included in the relevant MEG are defined for a MEG. Specifically, the MEG levels clearly discriminate and separate the processing flow in the MEG and the processing flow in other MEGs. There are defined eight levels (0 to 7), the default level allocation is shown in FIG. 28. The respective levels shown in FIG. 28 are stored in all Ethernet-OAM frames, and checked by an apparatus that has received an OAM frame.
A MEP is positioned at the terminal point of a MEG. A MEP generates and terminates (incorporates) an OAM frame for failure management and measuring performance, and does not terminates but only monitors frames other than an OAM (for example, counts the number of frames). A MEP is assigned with an ID (a number from 1 to 8191) referred to as a MEPID, which does not have any overlaps in same MEG. A MIP is positioned at the intermediate point of a MEG. A MIP executes processing on various OAM frames. However, a MIP does not generate or terminate an OAM frame and does not have an ID.
In the above configuration, OAM frames are transmitted between MEPs. The OAM frames include test data such as connectivity, paths, defect notification, and service state transition. Then, when the MEP or the MIP receives the OAM frames, executes processing depending on the kinds of the OAM frames. Afterward, it is analyzed whether or not the MEP and the MIP are in correct operation from a result of the execution, thereby distinguishing whether or not a relay apparatus such as each MEP or MIP implements the Ethernet-OAM.